Nordic Concrete Research最新文献_第3页

Application of an Improved Empirical Model for Rheology Prediction of Cement Pastes Modified with Filler from Manufactured Sand 改进经验模型在砂填料改性水泥浆体流变预测中的应用

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Nordic Concrete Research Pub Date : 2021-12-01 DOI: 10.2478/ncr-2021-0005

E. L. Skare, Rolands Cepurītis, Ernst Mørtsell, S. Smeplass, J. Spangenberg, S. Jacobsen

{"title":"Application of an Improved Empirical Model for Rheology Prediction of Cement Pastes Modified with Filler from Manufactured Sand","authors":"E. L. Skare, Rolands Cepurītis, Ernst Mørtsell, S. Smeplass, J. Spangenberg, S. Jacobsen","doi":"10.2478/ncr-2021-0005","DOIUrl":"https://doi.org/10.2478/ncr-2021-0005","url":null,"abstract":"Abstract There is a need for simple but precise prediction models for proportioning concrete with manufactured sand, for use in ready-mix concrete production. For the last two decades, the particle-matrix model has been used in Norway for proportioning and prediction of concrete flow based on the properties and proportions of two concrete phases: coarse particles and filler modified cement paste (matrix). This paper presents experimental testing of 117 cement pastes of which 107 contain filler, i.e. particles < 125 microns, from manufactured sand. Based on compositions and properties of ingoing materials in these mixes, an empirical equation is developed that predicts the rheological properties plastic viscosity, yield stress, flow resistance ratio and mini slump flow. Optimization by regression analysis provides a practical microproportioning equation that readily can be used as input in concrete proportioning with the particle-matrix model. The equation provides a coefficient of determination R2 = 0.98 for plastic viscosity, R2 = 0.95 for mini slump flow, R2 = 0.91 for flow resistance ratio and R2 = 0.80 for yield stress.","PeriodicalId":42762,"journal":{"name":"Nordic Concrete Research","volume":"6 1","pages":"1 - 18"},"PeriodicalIF":1.0,"publicationDate":"2021-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77784113","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Resonant Frequency Ultrasonic P-Waves for Evaluating Uniaxial Compressive Strength of the Stabilized Slag–Cement Sediments 共振频率超声p波评价矿渣-水泥稳定沉积物单轴抗压强度

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Nordic Concrete Research Pub Date : 2021-12-01 DOI: 10.2478/ncr-2021-0012

P. Lindh, Polina Lemenkova

{"title":"Resonant Frequency Ultrasonic P-Waves for Evaluating Uniaxial Compressive Strength of the Stabilized Slag–Cement Sediments","authors":"P. Lindh, Polina Lemenkova","doi":"10.2478/ncr-2021-0012","DOIUrl":"https://doi.org/10.2478/ncr-2021-0012","url":null,"abstract":"Abstract Marine sediments can be stabilized by ultra high-strength binders: cement, Cement Kiln Dust (CKD) and slag. The properties of the stabilized soil indicate potential to their reuse. This study investigated the performance of the unconfined compressive strength (UCS) in the marine sediments stabilized by binder (cement, CKD, slag), tested by ultrasonic P-waves. Materials include 194 specimens collected from the port of Gothenborg. The experiment was performed in Swedish Geotechnical Institute (SGI). The UCS of specimens stabilized by different ratio of binders (cement, CKD, slag) was tested by resonance frequencies of the elastic P-waves. The significant increase in the UCS (>1500 kPa) was recorded for the highest values of CKD and cement, and low values of slag. The correlation profiles of low water/high binder (LW/HB) cement/slag (40/60%) were controlled by curing time. The slag–cement–CKD simplex tests demonstrated UCS of samples with low/high water content and various binder ratio of cement (kg/m3). The ratio of cement binder and curing time play a critical role in the increase of UCS followed by mechanical properties of specimens and intensity of stress. The highest values exceed 1000 m/s in P-waves. The results shown high accuracy (97%) and non-contacting approach for testing UCS of sediments. Seismic methods can be applied to test the UCS of the stabilized sediments, and also in-situ via seismic CPT, surface testing or cross hole seismic testing.","PeriodicalId":42762,"journal":{"name":"Nordic Concrete Research","volume":"11 1","pages":"39 - 62"},"PeriodicalIF":1.0,"publicationDate":"2021-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87527276","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 20

Towards Efficient Use of Cement in Ultra High Performance Concrete 在超高性能混凝土中高效使用水泥

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Nordic Concrete Research Pub Date : 2021-12-01 DOI: 10.2478/ncr-2021-0017

I. Lande, R. T. Thorstensen

{"title":"Towards Efficient Use of Cement in Ultra High Performance Concrete","authors":"I. Lande, R. T. Thorstensen","doi":"10.2478/ncr-2021-0017","DOIUrl":"https://doi.org/10.2478/ncr-2021-0017","url":null,"abstract":"Abstract This paper presents an investigation on substituting the cement content with an inert material, in a typical locally produced UHPC mix. A structured literature review was performed to enrichen the discussion and to benchmark the results towards already reported investigations in the research society. Investigations on cement substitution in UHPC are frequently reported. However, usually the cement is substituted with other binding materials – often pozzolanic by-products from other industries. Reports from investigations on the use of inert materials for cement substitution in UHPC seem scarce. An experimental program that included a total of 210 test specimens was executed. This program included evaluating several questions embedded to the problem on how to substitute cement while keeping all other variables constant. It is concluded that up to 40% of the cement can be substituted with an inert material, without significantly changing the flexural tensile strength or compressive strength of the hardened UHPC. Two preconditions were caretaken: the particle packing was maintained by securing that the substitution material had a Particle Size Distribution (PSD) near identical to the cement and that the water balance was maintained through preconditioning of the substitution material. Suggestions are made for improving benchmarking.","PeriodicalId":42762,"journal":{"name":"Nordic Concrete Research","volume":"61 1","pages":"81 - 105"},"PeriodicalIF":1.0,"publicationDate":"2021-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85292618","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Numerical Modelling of Heat Transport in Freezing Mortars with an External Liquid Reservoir 带外储液器的冻结砂浆热输运数值模拟

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Nordic Concrete Research Pub Date : 2021-12-01 DOI: 10.2478/ncr-2021-0019

A. Faheem, Maxime Ranger, Marianne Tange Hasholt

引用次数: 0

Evaluation of Rapid Repair of Concrete Pavements Using Precast Concrete Technology: A Sustainable and Cost-Effective Solution 使用预制混凝土技术快速修复混凝土路面的评估:一种可持续和经济的解决方案

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Nordic Concrete Research Pub Date : 2021-12-01 DOI: 10.2478/ncr-2021-0018

Saima Yaqoob, J. Silfwerbrand, L. Strömberg

{"title":"Evaluation of Rapid Repair of Concrete Pavements Using Precast Concrete Technology: A Sustainable and Cost-Effective Solution","authors":"Saima Yaqoob, J. Silfwerbrand, L. Strömberg","doi":"10.2478/ncr-2021-0018","DOIUrl":"https://doi.org/10.2478/ncr-2021-0018","url":null,"abstract":"Abstract Concrete and asphalt are the two competitive materials for a highway. In Sweden, the predominant material for the highway system is asphalt. But under certain conditions, concrete pavements are competitive alternatives. For example, concrete pavements are suitable for high-traffic volume roads, roads in tunnels, concentrated loads (e.g., bus stops and industrial pavement). Besides the load-carrying capacity, the concrete pavement has many advantages such as durability (wear resistance), resistance against frost heave, environment (pollution, recycling, and low rolling resistance leading to fuel savings), fire resistance, noise limitations, brightness, evenness and aesthetics. Concrete pavements are long-lasting but need final repair. Single slabs may crack in the jointed concrete pavement due to various structural and non-structural factors. Repair and maintenance operations are, therefore, necessary to increase the service life of the structures. To avoid extended lane closures, prevent traffic congestions, and expedite the pavement construction process, precast concrete technology is a recent innovative construction method that can meet the requirement of rapid construction and rehabilitation of the pavement. This paper evaluates rapid repair techniques of concrete pavement using precast concrete technology by analysing three case studies on jointed precast concrete pavements. The study showed that the required amount of time to re-open the pavement to traffic is dramatically reduced with jointed precast concrete panels.","PeriodicalId":42762,"journal":{"name":"Nordic Concrete Research","volume":"29 1","pages":"107 - 128"},"PeriodicalIF":1.0,"publicationDate":"2021-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86072712","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Static and Dynamic Four-Point Flexural Tests of Concrete Beams with Variation in Concrete Quality, Reinforcement Properties and Impact Velocity 混凝土质量、配筋性能和冲击速度变化的混凝土梁静、动四点弯曲试验

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Nordic Concrete Research Pub Date : 2021-12-01 DOI: 10.2478/ncr-2021-0007

V. Peterson, A. Ansell

引用次数: 0

Nonlinear Analysis of Reinforced Concrete Shear Walls Using Nonlinear Layered Shell Approach 钢筋混凝土剪力墙非线性层状壳分析

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Nordic Concrete Research Pub Date : 2021-12-01 DOI: 10.2478/ncr-2021-0014

A. Vatanshenas

引用次数: 1

Visible Corrosion Damage in Carbonated Reinforced Concrete 碳化钢筋混凝土的可见腐蚀损伤

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Nordic Concrete Research Pub Date : 2021-12-01 DOI: 10.2478/ncr-2021-0015

Alina Lahdensivu, J. Lahdensivu

{"title":"Visible Corrosion Damage in Carbonated Reinforced Concrete","authors":"Alina Lahdensivu, J. Lahdensivu","doi":"10.2478/ncr-2021-0015","DOIUrl":"https://doi.org/10.2478/ncr-2021-0015","url":null,"abstract":"Abstract This study discusses visible corrosion damage due to carbonation in concrete balconies and facades. The focus of the study was to find out how the age of the structure, cover depth of concrete, carbonation coefficient, capillarity of concrete and the climate affect visible corrosion damage. The research data consist of condition investigation reports of existing concrete balconies and facades built between 1948 and 1996. Balcony slabs and brushed painted facades were the most prone to visible corrosion damage. None of the researched panels met the required minimum cover depth of reinforcement even at the time of construction. However, most of the visible damage on the database was localized damage and there was not much visible corrosion damage. The carbonation coefficient of balconies was higher than the carbonation coefficient of facades. Brushed painted facade panels had clearly higher carbonation coefficient than other facade panels. The carbonation coefficient was considerably lower on white concrete panels compared to other panel types. When capillarity of concrete raises, the carbonation rate of concrete increases slightly. However, no correlation can be seen. The capillarity of concrete and the carbonation rate of concrete had a major range.","PeriodicalId":42762,"journal":{"name":"Nordic Concrete Research","volume":"24 1","pages":"129 - 148"},"PeriodicalIF":1.0,"publicationDate":"2021-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86750939","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Effects of Slag Addition and Mechanical Pre-Processing on the Properties of Recycled Concrete in Terms of Compressive Strength and Workability 掺渣和机械预处理对再生混凝土抗压强度和和易性的影响

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Nordic Concrete Research Pub Date : 2021-06-01 DOI: 10.2478/ncr-2020-0018

Madumita Sadagopan, K. Malaga, M. Lundin, A. Nagy

{"title":"Effects of Slag Addition and Mechanical Pre-Processing on the Properties of Recycled Concrete in Terms of Compressive Strength and Workability","authors":"Madumita Sadagopan, K. Malaga, M. Lundin, A. Nagy","doi":"10.2478/ncr-2020-0018","DOIUrl":"https://doi.org/10.2478/ncr-2020-0018","url":null,"abstract":"Abstract Concrete waste as crushed concrete aggregates (CCA) in structural concrete prolongs the technical life of the reference concrete accomplishing closed loop recycling. CCA concrete reaches the reference concrete compressive strength and workability by the densification of CCA and cement paste. Our previous study demonstrates CCA densification by mechanical pre-processing, aggregate quality improvements discerned by increased packing density giving reference concrete strength and workability. This study addresses paste densification with blast furnace slag (GGBS) to replace 30 (wt.%) of Portland cement at reference concrete w/b ratio 0.5 and a lower w/b 0.42. Two CCA replacements are investigated: fine aggregates, CCA50; overall aggregate replacement, CCA100. Compressive strength results show that both CCA50, CCA100 mixes achieve reference values at w/b 0.42, only CCA100 achieves reference value at w/b 0.5 as a climate-optimized concrete. The CCA50 mix-w/b 0.5 reaches reference strength when paste densification by GGBS is combined with CCA densification from mechanical pre-processing of aggregates. The 7-day strength of CCA100 with GGBS increases by 11% by mixing with pre-soaked GGBS. Statistical analysis of CCA100 strength results shows significant improvements with GGBS compared to mechanical pre-processing. Significant improvements are possible in CCA50 mix for a combination of mechanical pre-processed aggregates and GGBS replacement.","PeriodicalId":42762,"journal":{"name":"Nordic Concrete Research","volume":"3 1","pages":"11 - 29"},"PeriodicalIF":1.0,"publicationDate":"2021-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80257854","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Service Life of Concrete Pedestal without Air Entrainment 无引气混凝土基座的使用寿命

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Nordic Concrete Research Pub Date : 2021-06-01 DOI: 10.2478/ncr-2021-0008

Niko Lindman, J. Kallio, J. Lahdensivu

{"title":"Service Life of Concrete Pedestal without Air Entrainment","authors":"Niko Lindman, J. Kallio, J. Lahdensivu","doi":"10.2478/ncr-2021-0008","DOIUrl":"https://doi.org/10.2478/ncr-2021-0008","url":null,"abstract":"Abstract Service life of nine wind power unit pedestals, which concrete grades between C45 and C55, were studied with four different service life models. The exact service life could be calculated only with two of them with the initial data. The service life models that were used in calculations: • Factor method • Deterioration and service life prediction of concrete subjected to freeze-thaw cycles in Na2SO4 Solution-method Service life models that were considered only at theoretical level: • FIB Bulletin 34 – Model Code for Service Life Design, and • An equation for determining freeze-thaw fatigue damage in concrete and a model for predicting the service life. The latter two methods are more theoretical, and they require laboratory tests to obtain more information before the calculations can be properly executed. This article concludes that damage to concrete due to freeze-thaw cracking is still poorly known and a sufficiently accurate service life model has not yet been developed for its computational modeling. Therefore, there is a need to develop a service life model suitable for Finnish climate and concrete grades, which could be used for estimating the damage rate of an existing concrete structure.","PeriodicalId":42762,"journal":{"name":"Nordic Concrete Research","volume":"19 1","pages":"93 - 107"},"PeriodicalIF":1.0,"publicationDate":"2021-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83793805","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0